NY Naturalization Records == On image 1 and 2 the place of birth is

Lisa Kay Horlacher

Port of Spain, Trinidad, BWI. I've seen the BWI in other documents. Is it an abbreviation for British West Indies? If so, should I type it out or leave it abbreviated?

https://www.familysearch.org/indexing/batch/b12fbc2f-a164-484b-832d-e29045381668

Melissa S Himes

You should spell out British West Indies.

erutherford

Yes, it is an abbreviation for British West Indies and since you know what the abbreviation stands for, you should spell it out. From the Birthplace Field Help:

You should expand abbreviations or correct misspellings when you can tell what the abbreviation stands for or what the correction should be to the spelling. 

Trinidad, in 1948, was still a British Crown colony, hence the British West Indies. It wasn't until 1962 did it gain its independence from the United Kingdom. Even though Trinidad British West Indies does not exist in 2023, just like Yugoslavia does not exist, we'll still index as British West Indies so the researcher can see that his/her relative was born while it was a Crown colony.